Search results for "phase separation"
showing 10 items of 62 documents
Polymer mixtures in confined geometries: Model systems to explore phase transitions
2005
While binary (A,B) symmetric polymer mixtures ind = 3 dimensions have an unmixing critical point that belongs to the 3d Ising universality class and crosses over to mean field behavior for very long chains, the critical behavior of mixtures confined into thin film geometry falls in the 2d Ising class irrespective of chain length. The critical temperature always scales linearly with chain length, except for strictly two-dimensional chains confined to a plane, for whichT; c ∝N; 5/8 (this unusual exponent describes the fractal contact line between segregated chains in dense melts in two spatial dimensions, d = 2). When the walls of the thin film are not neutral, but preferentially attract one …
Surface-directed spinodal decomposition: Lattice model versus Ginzburg-Landau theory
2009
When a binary mixture is quenched into the unstable region of the phase diagram, phase separation starts by spontaneous growth of long-wavelength concentration fluctuations ("spinodal decomposition"). In the presence of surfaces, the latter provide nontrivial boundary conditions for this growth. These boundary conditions can be derived from lattice models by suitable continuum approximations. But the lattice models can also be simulated directly, and thus used to clarify the conditions under which the Ginzburg–Landau type theory is valid. This comparison shows that the latter is accurate only in the immediate vicinity of the bulk critical point, if thermal fluctuations can also be neglecte…
Composites poly-lactic acid - hydroxyapatite scaffolds prepared via Thermally Induced Phase Separation
2013
USO DI TECNICHE AVANZATE PER LA OTTIMIZZAZIONE STRUTTURALE E FUNZIONALE DI SCAFFOLD COMPOSITI POLIMERO-CARICA INORGANICA PER LA RIGENERAZIONE OSSEA.
2020
AN EXPERIMENTAL APPARATUS TO CHARACTERIZE PHASE SEPARATION IN POLYMER SOLUTIONS
2013
Measurement of cloud point temperature in polymer solutions
2013
Evidence of Mechanisms Occurring in Thermally Induced Phase Separation of Polymeric Systems
2014
Thermally induced phase separation is a fabrication technique for porous polymeric structures. By means of easy-to-tune processing parameters, such as system composition and demixing temperature, a vast latitude of average pore dimensions, pore size distributions, and morphologies can be obtained. The relation between demixing temperature and morphology was demonstrated via cloud point curve measurement and foams fabrication with controlled thermal protocols, for the model system poly-l-lactide–dioxane–water. The morphologies obtained at a temperature lower than cloud point showed a closed-pore architecture, suggesting a “nucleation-and-growth” separation mechanism, which produced larger po…
Characterization of PLLA scaffolds for biomedical applications
2017
The porosity and pore size distribution of three-dimensional scaffolds have direct implications on their biomedical applications (tissue engineering, drug delivery, and wound dressing). Accordingly, in this paper, a fast, facile, and conservative method relying on low-field nuclear magnetic resonance (LF-NMR) for the evaluation of mean pore size and pore size distribution of polymeric scaffolds is reported. The applicability of the technique is demonstrated on poly-L-lactic acid scaffolds fabricated using the thermal induced phase separation. Results obtained through LF-NMR are successfully compared to scanning electron microscope and X-ray microcomputed tomography micrographs.
Dual film-like organelles enable spatial separation of orthogonal eukaryotic translation
2021
Summary Engineering new functionality into living eukaryotic systems by enzyme evolution or de novo protein design is a formidable challenge. Cells do not rely exclusively on DNA-based evolution to generate new functionality but often utilize membrane encapsulation or formation of membraneless organelles to separate distinct molecular processes that execute complex operations. Applying this principle and the concept of two-dimensional phase separation, we develop film-like synthetic organelles that support protein translation on the surfaces of various cellular membranes. These sub-resolution synthetic films provide a path to make functionally distinct enzymes within the same cell. We use t…